The serine protease inhibitor Alpha- 1 -antitrypsin (Alpha- 1 -AT) is synthesized primarily in the liver, then secreted into the blood where it is important in the physiological regulation of neutrophil elastase. In mice, alpha 1 -AT is encoded by a small multigene family of 2-4 functional members. Alpha 1 -AT expression is regulated in mammals in a developmentally and tissue-specific manner. This gene family therefore represents an excellent model system with which to study important regulatory factors which can control the tissue and temporal expression of mammalian genes. We have defined cis- and trans- acting elements which are important for expression of an Alpha 1-AT gene in cultured cells are necessary and sufficient to ensure tissue-specific and temporally correct expression in vivo. To carry out this analysis, we propose to introduce test constructs of the Alpha 1 -AT gene into fertilized mouse eggs and then to implant these eggs into the uteri of pseudopregnant female mice to generate transgenic offspring. An analysis of the DNA sequence elements required for the expression of test genes in transgenic animals will permit an unambiguous assignment of the cis-acting DNA elements required in vivo for tissue-specific and temporal expression of the Alpha 1-AT gene. A primary goal in this work is to develop the methodologies required for the generation and maintenance of transgenic mice. Besides its value to this project, the establishment of this technology within the Liver Center will make similar studies for other Liver Center investigators much simpler, since we could then collaborate or provide training for others requiring this powerful technology.